We all want our lawns to be as attractive and perfect as can be. But occasionally, certain unwanted growths creep up and make our beloved grass less than ideal.
Not only are lawn weeds unsightly, but they also take away valuable nutrients from the grass, which affects the health and growth of your lawn. If left unchecked, lawn weeds can even cause lawn disease.
CONTROLLING LAWN WEEDS
Sometimes we hope that getting rid of the growing lawn weeds is as simple as just lawn mowing and hand weeding. Sometimes that could work for prevention and if there are only a few weeds on your lawn.
Even though lawn mowing is one effective way to control and prevent certain types of lawn weeds, most types of weed are very resilient and could quickly establish their root system and spread their seeds before you even realize they are there.
Weed Prevention
The best way to prevent lawn weeds from taking over your lawn is by making sure that your grass is healthy and strong like coring your lawn or applying topsoil every year. Healthy turf will deprive weeds of the nutrients required for their growth.
Some also suggest keeping your lawn grass long and to not cut too much in one mowing session. Long leaves will give your grass a chance to absorb more air and sunlight, while depriving potential weeds of getting any, thus preventing their growth.
Once you notice weeds on your lawn, keep on top of it and remove them as quickly as possible. It is better to remove and take care of a few weeds as soon as possible, so they do not propagate and spread.
Herbicides
For more stubborn lawn weeds, you may need to take more drastic measures to keep your lawn protected and as healthy as possible.
The most common way to control weeds in the lawn is by using the appropriate herbicide. Make sure that you carefully read the manufacturer’s instructions and follow them diligently.
If you will use a pre-emergent herbicide, identify the lawn weed and find out when the seeds germinate. If you apply the pre-emergent too early or too late, the application may not be as effective.
Another thing to remember is to identify the type of grass you have if you are using a selective herbicide to avoid damaging your lawn grass.
There are times when the application of herbicides need to be repeated after a few weeks to ensure that the lawn weeds are under control.
Also remember to wear personal protective equipment or PPE such as eye protection, gloves, protective mask, long-sleeved shirt, long pants, and boots. Check out our Selective Herbicide Guide here.
LAWN WEEDS
Before we can get rid of them, we need to identify the type of lawn weeds we have correctly. If you fail to identify the weeds on your lawn correctly, your method of treatment may not be sufficient, causing you to waste time and money, and maybe even damage your lawn grass.
There are three categories of the most common lawn weeds: grass weeds, sedges, and broadleaf weeds. Written here are examples of some of the most common in these categories.
Grass Weeds
Grass weeds are any unwelcome grass on the lawn. Some of them are harder to detect early on because they can look similar to the grass on your lawn until you take a closer look.
Grass weeds usually grow taller than the lawn grass. They become more noticeable as they mature, especially when they start growing flowers.
They are a nuisance on the lawn because they could grow and propagate quickly if left unchecked, just like most weeds.
Common Crabgrass (Digitaria sanguinalis)
The common crabgrass, also known as summer grass, is probably one of the most common and toughest lawn weeds to eliminate.
This annual grass has an inflorescence or a group of flowers that grow from very long and thin radiating branches. These flowers can either be reddish or purplish when mature.
Crabgrass leaves are yellowish-green, linear and hairy, and turn to deep red or maroon when mature. Its stems spread and branch out, and bend abruptly, just like the claws and legs of a crab.
Being a summer annual weed, it dies after about a year but leaves in the soil hundreds, if not thousands of weed seeds that could germinate and grow the following year. Because of this, you cannot simply pull the weeds out and forget about it.
Smooth Crabgrass (Digitaria ischaemum)
The d. ischaemum is another specie of crabgrass. It looks almost the same as the d. sanguinalis or common crabgrass except that the sheathe of the stems of the smooth crabgrass do not have hair.
Like the common crabgrass, the smooth crabgrass is a summer annual that grows throughout the summer period, produces a lot of seed head, and then dies at the first frost.
Crowsfoot Grass (Eleusine indica)
The crowsfoot grass is tufted with semi-upright or spreading stems. It is also sometimes called crabgrass, dog grass, goosefoot, goosegrass, or iron grass.
The e. indica looks similar to d. sanguinalis (crabgrass) at first, but they differ because the crowsfoot leaves grow in a bunch-type and lie flatter against the ground. The crowsfoot leaves also grow in folded form while the crabgrass’ leaves are rolled.
The flowers of the crowsfoot also tend to have shorter stems compared with the crabgrass, and the spikelets of crowsfoot are generally larger compared with the crabgrass.
You can usually find crowsfoot in areas with more compaction, such as places where there is heavy foot traffic.
Broad Leaf Paspalum (Paspalum mandiocanum)
The broad leaf paspalum is another hardy perennial lawn weed. It grows from seeds late in summer.
Its leaves enclose the stem and can be more than 10mm wide. They are bright green near the tip, and burgundy, brown, or maroon towards the inner section.
It has a clumping growth habit. Its small flowers grow from spikelets, and the stems can be up to 1 m long.
The broadleaf paspalum is mostly found in the shaded areas of the lawn.
How to Control Grass Weeds
Regular mowing will help control summer annual lawn weeds. Because most grass propagate through its seeds, cut the grass before they even mature and produce seeds.
Take care not to mow too low. Cut just enough to remove about a third of the grass.
You can also dig them out, making sure to remove all its roots.
In case these lawn weeds have matured and formed inflorescence, then a post-emergent can be applied on the matured weed to kill them.
A pre-emergent herbicide can be applied during the germinating period, which is usually in early spring, to keep the seeds from germinating the following growing season.
SEDGES
To the untrained eye, some sedges look like grasses. One way to differentiate them is where they grow—grasses grow in the drier places in your lawn, while the sedges prefer moist and wet soil.
Looking closer, grasses with have solid nodes on their hollow stems, while sedges do not have nodes and the culms are solid and often triangular.
Mullumbimby Couch (Cyperus brevifolius)
The Mullumbimby couch is a perennial weed and is considered very invasive. It prefers habitats that are moist, damp and shady.
The Mullumbimby couch has flowering stems with a three-angled cross-section. It has long and tough underground rhizomes where upright, straight flowering stems grow. Its pale green, ovoid seed heads produce yellow to reddish-brown seeds.
Nutgrass (Cyperus esculentus)
Another common sedge, the nutgrass is a perennial that is considered invasive. Just like most sedge weeds, it prefers a moist environment.
The nutsedge can grow up to 90 cm tall and has an extensive root system comprised of creeping rhizomes. Its stems have a triangular cross-section and three long and thin leaves grow from each.
You can usually spot the nutgrass because it is often taller and lighter green compared with the colour of the lawn grass.
How to Control Sedges
Sedges can be quite challenging to get rid of, so it is crucial to act as soon as you see them in your lawn.
Since sedges have rhizomes, only pulling them out will not eliminate the problem. They are hardy and stubborn, so digging them up is one way to remove them, taking care to get every part of its root and rhizomes.
If there is an excessive amount of them on your lawn, you can use a selective herbicide against them. Make sure to follow the instructions for effective application carefully, and to avoid damaging the rest of your lawn.
Sometimes you may need to repeat the application of herbicides to make sure that the weeds are eliminated.
BROADLEAF WEEDS
Broadleaf weeds on your lawn are easy to spot because they look nothing like grass. They are tough and can be a challenge to remove.
As the name suggests, broadleaf weeds have wide leaves compared with the grass that has long and thin leaves. They can either form a single or clusters of flowers when they mature.
Most broadleaf weeds have fibrous root systems. The taproot can either be thin or large or a combination of both.
Dandelion (Taraxacum officinale)
Dandelions are perineal weeds, most recognizable for their round yellow flower heads comprised of many small flowers. The leaves are toothed and usually gets broader at the tip and tapers as it goes down the centre.
The toothed leaves form a rosette. Because of its broad tips, the leaves cover the nearby grass, killing it by depriving it of sunlight.
Its flower head turns white upon maturity when it is ready to spread its seeds. That is the reason why dandelion flowers are popular, especially among children who blow on it to watch its tiny flowers fly into the air.
Even if it is popular and edible, a lot of times the dandelion is an unwelcome addition to the lawn.
Creeping Oxalis (Oxalis corniculata)
The creeping oxalis has heart-shaped leaves that some people might find attractive. However, most people do not welcome them on their lawn.
It produces small bright yellow flowers about 3-4mm each and has a habit of covering the ground and running along the surface. Even its leaves can produce roots.
White Clover (Trifolium repens)
Although white clovers have their practical uses in pastures, this perennial legume is unwelcomed and considered a lawn weed.
It has creeping stems and leaves with three leaflets. Its stems set their roots wherever they touch the soil.
The best way to prevent them is to make sure that your lawn is healthy and strong, especially in the warmer growing months.
Capeweed (Arctotheca calendula)
Capeweed belongs to the sunflower family. Its hairy leaves are deeply toothed or lobed and grow in a rosette. It can quickly spread across the lawn.
Small yellow flowers bloom from its hairy stems, with the petals extending out from the centre. It is sometimes used as an attractive groundcover but is invasive when they grow on the lawn.
Bindii Weed (Soliva sessilis)
Bindii, also jo-jo weed, is an erect rosette-forming annual weed that grows low and matting starting in winter and then flowers in spring. It is fast-growing, invasive and unsightly.
Its flowers develop into spiny and sharp seeds which can easily attach to your clothes or animal fur. The prickly seeds can also cause scratches and injury, especially for children and pets.
Stinging Nettle (Urtica urens)
Stinging nettles can be a pain to remove from your lawn, literally! Its fine hairs can sting as they pierce through the skin.
While nettles are edible and have nutritional value, it is invasive and can quickly take over the lawn and deprive your grass of nutrients.
Take precautions when removing them and wear protective gloves to avoid injury.
Fat Hen (Chenopodium album)
The fat hen, also known as white goosefoot, is an annual broadleaf weed that grows upright at first and can reach up to 150 cm tall.
Its first leaves are toothed and diamond-shaped, and upper leaves by the flowering stems are rhomboid and waxy-coated.
Its flowers form in radially symmetrical clusters, 10 to 40 cm long.
How to Control Broadleaf Weed
Broadleaf weeds will keep reproducing and if not controlled, will take over the lawn where they started sprouting.
It is essential to identify the type of broadleaf weed in your lawn to know their growing habits and season.
If you only have a few lawn weeds, you can consider hand weeding to get each of them out, making sure to dig deep down to its root system.
If you have more weeds in your lawn than you can remove through hand weeding, then the better alternative is to use a post-emergent broadleaf herbicide applied through spot-treatment or a broader sprayer.
You can add surfactants if the lawn weeds have waxy or hairy foliage to ensure that the herbicide will stay and absorbed by the weeds.
If your lawn is infested with weeds it might be a good idea to just replace the lawn. Check out our Instant Lawn Hobart services page for more information.
If your lawn has brown patches don’t forget to check out our lawn pests guide.